Finally back in the car. Secured and sealed up. A difficult part was lining it up against the heater directional box. It was catching the hot to cold flap, which I turned to hard!!! So lesson to all, take your time and you won't have to reset the dash controls. Since working it out the Hot to Cold flap now turns incredibly smoothly.
There is however no way of securing the two units together, so I used a tyrap to hold it up and in line, some sticky sponge to seal and close the gap, then gaffa tape all around. A very efficient system now. Fingers crossed that I can get it pressure tested soon and that it won't leak.......
Be interesting to see if this converted mk4 golf evaporator does the job, especially after all this time and money.